This invention relates generally to cargo compartments of pickup trucks. More particularly, this invention pertains to upstanding extension walls and means for attaching such extension walls to the cargo compartment of a pickup truck for increasing the load capacity.
Conventional pickup truck cargo compartments consist of a pair of spaced sidewalls rigidly connected to a supporting floor. A front wall interconnects the forward ends of the side walls and a tail gate typically spans the rear end of the cargo compartment. The sidewall, front wall and tail gate extend a relatively short distance above the floor, limiting the capacity of the compartment. Efforts have been expended in developing extension walls for increasing the capacity of pickup trucks and other vehicles.
An early form of upwardly extending wall panel is typified in U.S. Pat. No. 979,309 of Johnston. The panel is held in place by two sets of cleats and an external clamp. The use of cleats for attaching an extension wall panel to a pickup truck cargo compartment is impractical because of the complex shape of the compartment's side walls. The clamp requires the drilling of holes in the pickup truck, and is designed for permanent installation.
An apparatus found useful by a large number of pickup truck users is the tie-down which is fitted into a stake pocket. A common form of the tie-down includes an exterior annulus such as an eye hook, and an expansion member which is inserted and locked in a stake pocket. The apparatus of the Johnston patent would require removal of any installed tie-downs prior to installation of the extension wall panels.
Other extension wall panels are attached to the pickup truck by stakes which are installed in the stake pockets. The stakes may be fixed to the wall panel, as in U.S. Pat. Nos. 4,585,264 of Miller and 2,711,342 of Selzer. Alternatively, sliding stakes may be used, as shown in Selzer U.S. Pat. No. 2,856,225. In each of these versions, any tie-downs installed in the stake pockets must first be removed. In addition, the particular fasteners used are mounted on the external walls of the panels so that the extension wall panels do not have a smooth, aerodynamic exterior but have visible fasteners and/or other extraneous apparatus on the wall exterior.
None of the wall structures of these patents may be interchangeably installed on cargo compartments having varying spacing between the stakes, or having a variable number of stakes.